Radiocontrol system



W. E. BRINDLEY RADI OCONTRQL SYSTEM Filed May 20, 1926 as mac Aug. 9, 1932.

WITNESSES: ,OZWM/ Patented Aug. 9, 1932 WILLIAM E. BRINDLEY, or WILKINSBURG, PENNSYLVANIA, ASSIGNOR T0 WESTING- HOUSE ELECTRIC & MANUFACTURING VANIA COMPANY, A. coaronArroN or PENNSYL- RADIOGONTROL SYSTEM Application filed May 20,

My invention relates to systems of communication, and it has particular reference to systems applicable to communication between the vehicles of a movable train.

Generally, when hauling heavy trains by electric locomotives it has been found necessary to use a plurality of propulsion units, placing one or more at the head of the train and one or more at the rear.

Some freight trains often attain a length of one mile or more, and it is apparent that reliable means-of communicationbetween the front locomotives and those at the rear is a matter of extreme importance in order tosecure synchronous action in starting and stopping. It has been the custom in steam railway work to signal by means of the steam whistles carried by the engines. This practice is fairly reliable if other noise does not interfere. The air whistles used on electric locomotives, however, cannot be heard satisfactorily at any great distance, or through tunnels. It-is, of course possible to provide a direct electricalconnection between the front and rear and to operate some type ofa signalling system, either telephonic, telegraphic, or the like. These means of communication, however, fail when the train breaks into sections and it :is at such times that uninterrupted communication between the various component parts of the train is of vital importance.

It is, accordingly an object of my invention to provide a communication system, particularly adaptable for use on trains equipped with electric locomotives.

Another object of my invention is to provide a simple and easily operated system of communication between the vehicles comprising a train.

Another object is to provide a system of communication which will not be hampered by reason of the train breaking into sections.

Still another object of my invention is to provide a train signalling system which may be operated from any portion of the train and which will convey intelligence between the men in charge of each propulsion unit thereof.

I attain these objects, and others'of a more 1926. Serial N0. 110,353.

specific nature which will be clearly explained, in the following manner.

In each of the propulsion units I install a radio transmitter and receiver. An antenna fed by the transmitter is arranged on top of mounted in steel boxes rigidly built to With-.

stand vibrations. A motor generator,"driven either from a storage battery or .fromthe source of power operating the locomotive,

furnishes the high voltage for the plate -l' tubes. Other cursupply to'the transmitting) t M t y sui a e s orage rent needs are supplied batteries. The receiver may be the ordinary detectoramplifier system, the tuning of which is usually'set and remains fixed, but which may be variable. v

' I prefer toso arrange the equipmentassociated with the transmitter that either sigrials of the usual type may be sent, or the output of the transmitter may be modulated by a microphone, enabling voice'communication between various portions of the train. To accomplish this result, a small control box, which is attached to the ceiling of the locomotive cab, contains a switch device equipped with a plurality of'contact-1nembers. These contact members control relays adapted to close or open the circuits involved in either code-signalingor voice transmission. To this i switch is attached a cord that hangs within easy reach of the engineerin charge of the locomotive'and which takes the place of the whistle cord to which he has become accustomed.

When the engineer desires to-signal, he pulls the signal rope half-way from the control box. This starts a motor-generator which energizes an oscillation generator. sending high-frequency current over the trolley wires. =He then pulls the signal rope further which closes contact members controlling an audio-frequency modulator coupled to the oscillation generator. By slightly lessen? ing the pull on the rope, the modulator is {.2

7 had, 7

rendered inactive, and in this manner code signals may be radiated. In order to communicate by voice, the engineer first sends an agreed-upon code signal and then pulls the cord all the way down which breaks the audio-frequency modulator circuit and connects a microphone in circuit instead.

The microphone and attendant circuits may be dispensed with, if desired, signals in that case beingsent by code only. The signal being sent by one engineer is also heard by him, inasmuch as his receiving set is at all times kept in an operative state and is coupled to the trolley wire in the same manner as is the receiving set of the engineer at the other end of the train. This is advantageous, as it enables each engineer to know exactly what signals he is sending out. ,7

Referring now to the'drawing and the following description, from which a more complete understanding of my invention may be Figure 1' is a diagrammatic 'elevational view of a train equipped with: apparatus according to my invention. i Fig.2 is a diagrammatic View of the circuits and apparatus involved. v Referring specifically to Fig. 1, a plurality of electric locomotives 1, 2 and 3 are coupled together forming one propulsion unit which may be either at'the front or rear end of a train, composed of a plurality of cars 4,15 and 6. At the other end of the train is a similar propulsion unit comprising a plurality of electric locomotives 7 8 and 9. Each of these locomotives draws current from the trolley wire 10 through a pantograph 11. One loco motive of each group of three is equipped with I an antenna 12 and a transmitter 18. Each locomotive is, equipped with 'a signalling cord and switch 14 'and the'control circuits between the locomotives are carriedby aconduit 15'. I The functionsot the v'arious'pieces of apparatus indicated in Fig. 1 will be more clearly brought out later in the description, this figure showing merely the relation between the locomotives, the train, the trolley wire, the antennas, and the radio transmitters.

Referring specifically to Fig. 2,a switching arrangement 14' having an actuating means 14 is provided with a plurality oi contact members-16,17, 18,20 and 21.; Abattery 22 is provided, included incircuitwith which are a plurality of relays 23, 24 and 25. The relay23 has a plurality of contact members 26 and 27 which serveto'open' or close a circuit'comprising a battery 28 and a motor 29. Mechanically coupled to this motor 29 is a direct-current generator -30 'for supplying plate voltage to the thermionic tubes. 7 The relay 24 has two contact members 32 and 33 whichservc to make-and break a circuit through abattery 34, microphone 35 and a primary winding 36 of an input transformer 37. The secondary 38 of this input transformer is connected between the filament 39 and the grid 41 of a thermionic'modulator tube 42. In series in this input circuit comprising the secondary 38 is a primary winding 43 of a second transformer 44, the secondary v45 of which is connected in series between the ductances 48 and 49. Shunted across between. the-leads 51 and 52 from the source 54 land 55. y

The relay 25 has contact members .56 and 57 which, in their normal position short circuit the winding 45. The plate 46 of the modulator tube is conductively coupled through a lead 59, the primary 45, and the choke coil 47 to the plate 61 of a thermionic oscillator tube 62. The oscillator tube 62 is provided with a filament 63, a source of filament potential 64, a grid 65, and a combined input-output inductor 66 so arranged thatcontinuous oscillations may be maintained therein. Any well known thermionic oscillation generator may be substituted for the type I have illustrated, as this forms no part'of myinvention. The oscillationgenerator'is coupled to the antenna 12 either by means of a choke 67 a condenser (not shown) or in some other well known manner. Also coupled to the antenna 12 is a detector-amplifier'systeni 68, the output of which may actuate a plurality of loud speakers 69, 707 and 71, located wherever expedient, but usually in proximity to the signal Cords 14. =I-Iaving now described the apparatus and circuits involved in my invention, the manner and sequence of its operation will be explained. .7 o As shown in Fig. l, the antennae oi the various transmitters are placed in close proximity to the trolley wire or wires from which the: locomotives derive current. Assuming that it'is desired to send a signal from one end of the train to the other, the engineer or other person desiring tosignal, first ascertains that the tube filaments in both transmitting and receivingsets are energized. He next grasps the signal cord 14 and pulls 30 are a plurality of by-pass condensers 53,

slightly thereon. This slight pull on the ele set up in the output circuit of the tube 62, which oscillations are conveyed to the antenna 12.

The set is now in readiness for signalling, which is accomplished by a further pull on the cord 14, causing contact members 17 and 18 to close. The closing of these contacts energizes a circuit which may be traced through contact members 18 and 21, the battery 22, relay 25 and back to contact 17. The energizing of relay 25 causes contact members 56 and 57 to open, removing the short circuit from the winding 45. The removal of this short circuit causes the tube 42 to set up oscillations at an audio frequency determined by the inductance of the windings 38 and 43 and the stray capacity of the circuit between the grid 41 and the filament 39.

Inasmuch as the modulator tube 42 and the oscillator tube 62 are fed in parallel from the same source of plate potential 30, the audiofrequency oscillations in the tube 42 will modulate at an audio frequency the high frequency oscillations being supplied to the antenna 12, as is well known to those skilled in the art. The choke coil 47 prevents radio frequency from the tube 62 from traversing the circuits of the modulator tube.

It is thus seen that each time the contacts 17 and 18 close, the output of the antenna 12 will be subjected to modulation at an audible frequency. This modulated high frequency is guided along the trolley wires and is picked up by the detector-amplifier set at the other end of the train. Since each detector-amplifier portion of the apparatus is permanently coupled to each antenna, the signals being sent out are audible to the sender as well as to the engineer at the distant end of the train.

Should it be desired to communicate by voice, the cord 14 is pulled sufficiently to carry the contact member 18 past, and out of engagement with, the contact member 17 and to engage the contact member 16. As soon as contact between the elements 17 and 18 is broken, the relay 25 is released and the contact members 56 and 57 engage, thereby short-circuiting the transformer secondary 45, which prevents the tube 42 from oscillating.

A circuit may now be traced through contact members 16 and 18, battery 22 and relay 24 and back to contact member 16. The energizing of the relay 24 causes the contact members 32 and 33 to come together, placing the microphone 35, the battery 34 and the transformer primary 36 in series with each other. Upon speaking into the microphone 35, the modulator tube 42 is energized and serves to modulate the high-frequency output of the tube 62.

It is thus apparent that the engineer at one end of the train may gain the attention of the engineer at the opposite end by a prearranged code signal and may then talk to 5 him directly, if desired. In some cases, howsupply lead 52 and a plurality of by-pass condensers 53, 54 and 55' in order to smooth out the direct-current supply.

I have merely indicated diagrammatically the type of switch I may employ, but itis obvious that any known type may be substituted therefor, provided the proper sequence of operations is maintained. Upon return of the contact member 18 toits initial position, it is desirable and expedient that contact'member 17 be missed during the upward travel. To secure this result, I mayfmake use of a switch similar to that shown in the patent to S. W. Rushmore, No. 1,079,725 granted November 25, 1913. This patent discloses a type of switch in which a movable deflector is interposed between two contacts in one direction of travel and is not interposed therebetween when the relative movement is in the opposite sense. I

A system constructed according to my invention has numerous advantages. The length of the train intervening between the two propulsion units is immaterial, and it is also apparent that even though the train break, communication will not be interrupted, and that one engineer can promptly apprise the other as to what steps to take.

The passage of the train through tunnels has presence of snow and ice on the trolley interferes in no way with satisfactory communication, and other weather conditions, which to some extent influence the travel of sound in air, have no effect on the high-frequency waves being guided by the trolley.

Another very decided advantage lies in the fact that if desirable, the transmitter might be of suflicient strength that a receiver at a central station could pick up the signals from any train along the route. In such cases, it would, of course, be necessary that each train employ a distinctive frequency. .The various trains may also communicate with each other in cases of necessity, it being only necessary to vary the tuning of receiver and transmitter for this purpose.

The feature of signalling from one vehicle to another vehicle by means of radiant energy sent over a guiding channel is claimed in application S. N. 565,756, filed Sept. 29, 1931, which is a division of the present application.

Although I have illustrated and described herein certain specific embodiments of my invention, I do not wish to be restricted therevto. I desire, therefore, that only such limitations shall be imposed as are indicated in the appended claims.

I claim as my invention:

1. In a radio system, energy radiating means, means comprising an oscillation generator for supplying energy to the radiating means, means for modulating the energy supplied .and a single means for sequentially causing the generation of oscillations and the modification thereof by said modulation means. I

.2. In a radio system, oscillation generating means, modulating means therefor, and a single operating means for successively causing the generation of oscillations and the modulation thereof.

3. In a signaling system, an antenna, means associated therewith'for supplying oscillatory energy thereto, modulating means for modifying said oscillatory energy, and a sequence switch, the-operation of which first causes the supp ying of said oscillatory energy to said antenna and then controls said modulating means. gti'In'a radiosystem, an oscillation generator, a plurality of modulating means, anda sequence switch havinga plurality of positions', in one of which it efi'ects the operation of the oscillation generatona second position for effecting the operation of one modulating means, and a third position for elfecting the operationof a second modulating means.

' In testimony whereof, I have hereunto subscribed my name this 17th day of May, 1926.

IVILLIAM E. BRINDLEY. 

